PHP read each file and search for string

Question

I am trying to write some code to look through all of the files in my server and return files that contain a certain string. The problem is that I only know the comment in the files I'm looking for is the key and I feel like this may be messing this up.

I have a function that recursively searches for files in all directories which works fine, but the reading of the file and searching of the string is not working properly.

<?php
$mal = "//###=CACHE START=###";


function getDirContents($dir) {
    $files = scandir($dir);
    foreach($files as $file) {
        if($file == "." || $file == "..") continue;
        if(!is_file($dir . $file)){
            echo "Folder: " . $dir . $file . "<br />";
            getDirContents($dir.$file."/");
        } else {
            echo "File: " . $dir . $file . "<br />";
            $content = file_get_contents($dir . $file);
            if (strpos($content, $mal) !== false) {
                echo "FOUND" . $dir.$file . "<br>";
            }
        }
    }
}

$dir = "./";
getDirContents($dir);


?>

For some reason, this is returning .png and .jpg files as "FOUND" and I'm not sure why. I have many files that have the $mal string in them, but it's a comment and I'm not sure if that matters. Either way, it is not working properly and not finding the files that I'm looking for.

pvg · Accepted Answer · 2016-12-17 08:24:59Z

3

This fails because the thing you're searching for is not actually in scope - in the function scope $mal is actually NULL and thus always found. This is outlined in the documentation at http://php.net/manual/en/language.variables.scope.php

<?php
$a = 1; /* global scope */ 

function test()
{ 
    echo $a; /* reference to local scope variable */ 
} 

test();

This script will not produce any output because the echo statement refers to a local version of the $a variable, and it has not been assigned a value within this scope. You may notice that this is a little bit different from the C language in that global variables in C are automatically available to functions unless specifically overridden by a local definition. This can cause some problems in that people may inadvertently change a global variable. In PHP global variables must be declared global inside a function if they are going to be used in that function.

A quick and dirty way to fix this is to declare $mal a global. Saner is to pass it in as a parameter to your function, along with the dir.

answered Dec 17, 2016 at 8:24

pvg

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9 Comments

ntgCleaner Over a year ago

Ah, that was a bonehead move! I remembered that with the $dir but not the $mal. Thank you. That half-solved my problem. Now, for some reason, I can't search for anything that is considered php code. I have done some testing and was able to find <div> in many files, but what I need to search for now is the comment string which seems to not be working.

pvg Over a year ago

@ntgCleaner that seems like a different question. More generally, there's probably not much point re-implementing grep in PHP when you can just call grep.

ntgCleaner Over a year ago

Well, I'm trying to find a block of code inside of multiple files so I may remove it. My server was compromised and I have found the infection point, I just need to go through all files on my server and remove this block of code, which is written in php, not as a string. Is there an option for this?

pvg Over a year ago

@ntgCleaner Yes. Wipe the server, install clean copy of code.

ntgCleaner Over a year ago

Haha, yes, that's my last resort. I've found the affected files and the security hole, I have a list of affected files from the server and I'm just trying to make my job quicker by writing a script do delete this block, rather than me doing it the slow way. - I just wrote a new question to target this specifically.

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